If you ask a random person on the street to list all the different types of running races, they will probably be able to list three or four, like the marathon and the 100m race. However, there are plenty more of these events and some of them are not in the Olympics. While the aforementioned two are typical representatives of their type of race, I feel like some explanation may be in order.
Track And Field
Track and field has 5 different events that are focused exclusively on running. Sprints come in different lengths, but the object is to run as fast as you can and there is no time to pace yourself.
Long-distance races, like the marathon, first demand that you have ample endurance and, with good pace-makers, you can work on your speed. Middle-distance races have events from 800m to 3,000m and combine the speed and the endurance of the previous two.
Hurdles are like sprint races, except you have to jump over hurdles, as the name says. There are no penalties when you knock them over, but, obviously, this slows you down considerably.
Finally, relay races are races with teams. Each runner runs a portion of the race and hands over a relay baton to the next runner in their team.
Road-running races are long-distance races that include marathons and half-marathons that usually have paved or tarmac roads. While today we have famous marathon events like the New York City Marathon, this type of race came from betting of the aristocrats on their own footmen in the olden days. These footmen would normally carry messages and items when speed was essential. Races became more popular and now this is a regular athletics event.
Cross Country Running
Cross country running takes place on grass, earth, and woodland trails. Some would say that it is the most natural of all racing events. Races can be single or team events and they are typically long-distance races.
I might get some hate for this one, but I am one of those that count racewalking as a running race event, even though there is no running involved. The racing events are done on the open road or running tracks. The point of this racing event is to see who is the fastest walker. Judges carefully monitor whether walking of the competitors becomes running at any point. One of the regulations is that one foot can’t rise before the other is set down.
Fun runs are enjoyable and sometimes outright ridiculous running events. There is not much focus on actual running and great results. As the name suggests, this is meant to be fun. Many fun run races have a theme, like running superheroes, or various obstacles, like those you see on Wipeout or something similar.
Ultra racing is, in fact, the opposite of fun runs. Ultra races are longer than marathons and are sometimes held in dangerous locations under extreme conditions. The most famous and arguably the toughest ultra race is Marathon De Sables in the Sahara. It is a six-day, 251 km ultramarathon, with the longest single-stage event being 91km. As much as I enjoy athletics, I am yet to muster the nerve to take one of these on.